A double circulation geothermal energy collection device

Abstract

This utility model relates to the field of energy utilization technology, and provides a dual-circulation geothermal energy harvesting device, which includes a heat collection pipeline and a heat exchange pipeline. The heat collection pipeline is a closed pipeline with a heat exchange medium flowing inside. The heat collection pipeline is laid in underground rock strata or soil to collect underground thermal energy. The heat exchange pipeline is arranged in parallel with the heat collection pipeline and forms a heat conduction contact. The heat exchange pipeline has an inlet connected to a surface water source through a water supply pipeline and an outlet connected to a surface water storage tank through a water supply pipeline. The above technical solution maximizes the contact area between the heat collection pipeline and the heat exchange pipeline by arranging them in parallel and forming a heat conduction contact, providing sufficient space for heat transfer. The design of opposite fluid circulation directions within the two pipelines forms a counter-current heat exchange mode. Compared with co-current heat exchange, counter-current heat exchange can maintain a larger temperature gradient along the entire contact length, thereby significantly improving heat transfer efficiency.

Description

Technical Field

[0001] The embodiments of this utility model relate to the field of energy utilization technology, specifically to a dual-cycle geothermal energy harvesting device. Background Technology

[0002] Geothermal energy, as a clean and renewable energy source, boasts advantages such as abundant reserves, wide distribution, and stable reliability, and has broad application prospects in building heating, power generation, and industrial heating. In the process of utilizing geothermal energy, the geothermal energy harvesting device is one of the key pieces of equipment, and its performance directly affects the utilization efficiency of geothermal energy.

[0003] Currently, existing geothermal energy harvesting devices typically employ a single-loop or simple dual-loop structure when collecting geothermal energy. These devices often suffer from inefficient layouts of the collector and exchange pipes, resulting in insufficient heat transfer contact and low heat transfer efficiency. This leads to incomplete harvesting of geothermal energy, wasted geothermal resources, and increased energy utilization costs. Utility Model Content

[0004] To overcome the above-mentioned defects, the embodiments of this utility model provide a dual-circulation geothermal energy collection device, which solves the technical problem of low heat exchange efficiency in geothermal collection in the prior art.

[0005] According to one aspect, at least one embodiment of the present invention provides a dual-cycle geothermal energy harvesting device, comprising:

[0006] The heat collection pipeline is a closed pipeline with a heat exchange medium flowing inside. The heat collection pipeline is laid in underground rock strata or soil to collect underground heat energy.

[0007] The heat exchange pipeline is arranged in parallel with the heat collection pipeline and forms a heat conduction contact. The heat exchange pipeline has an inlet connected to a surface water source through a water supply pipeline and an outlet connected to a surface water storage tank through a water supply pipeline.

[0008] The circulation direction of the fluid in the heat collection pipeline is opposite to that in the heat exchange pipeline.

[0009] For example, in a dual-circulation geothermal energy collection device provided in at least one embodiment of the present invention, the heat collection pipeline and the heat exchange pipeline are laid in a vertically downward direction, the heat collection pipeline and the heat exchange pipeline are nested together, and the heat collection pipeline is wrapped around the outside of the heat exchange pipeline.

[0010] For example, in a dual-circulation geothermal energy collection device provided in at least one embodiment of this utility model, the heat collection pipeline includes an outer tube and an inner tube located inside the outer tube. The upper ends of the outer tube and the inner tube are connected, and the lower ends of the outer tube and the inner tube are connected through a circulation pump installed on the inner tube to form a closed loop. The heat collection pipeline is located inside the inner tube, and a heat collection area is formed between the outer tube and the inner tube. A heat dissipation area is formed between the inner tube and the heat exchange pipeline.

[0011] For example, in a dual-circulation geothermal energy collection device provided in at least one embodiment of this utility model, the heat exchange pipeline includes an inlet pipe and a return pipe located inside the inlet pipe. The inlet pipe is disposed outside the return pipe. A first partition plate is provided at the lower end of the inlet pipe to separate the heat collection pipeline from the heat exchange pipeline. The lower ends of the inlet pipe and the return pipe are connected, and a heat exchange zone is formed between the inlet pipe and the return pipe. A return water zone is formed inside the return pipe. The inlet is formed at the upper end of the inlet pipe, and the outlet is formed at the upper end of the return pipe.

[0012] For example, in a dual-circulation geothermal energy collection device provided in at least one embodiment of the present invention, the lower end of the return water pipe extends to abut against the first partition plate and has a plurality of liquid passage holes on its side wall, the liquid passage holes being used to connect the heat exchange zone and the return water zone.

[0013] For example, in a dual-circulation geothermal energy collection device provided in at least one embodiment of the present invention, the heat collection zone is filled with gravel, which is used to enhance the heat exchange efficiency between the heat collection zone and the underground rock strata.

[0014] For example, in a dual-circulation geothermal energy collection device provided in at least one embodiment of the present invention, a second partition plate is provided on the inner wall of the bottom of the inner tube, the circulation pump is installed on the second partition plate, a liquid passage cavity is formed between the second partition plate and the bottom surface of the inner tube, the liquid passage cavity is connected to the heat collection area, and the circulation pump is used to pump the heat exchange medium in the liquid passage cavity into the heat dissipation area.

[0015] For example, in a dual-circulation geothermal energy collection device provided in at least one embodiment of the present invention, the wall of the return water pipe is made of heat insulation material to reduce the heat loss of the hot water in the return water pipe.

[0016] For example, in a dual-circulation geothermal energy collection device provided in at least one embodiment of this utility model, the water inlet pipe is segmented and spliced, and the water inlet pipe connection is connected by a flange.

[0017] For example, in a dual-circulation geothermal energy collection device provided in at least one embodiment of this utility model, the outer tube, the inner tube, the inlet pipe, and the return pipe are all coaxially arranged.

[0018] The beneficial effects of the embodiments of this utility model are as follows:

[0019] In this invention, the heat collection pipe and the heat exchange pipe are arranged in parallel to form a heat conduction contact, maximizing their contact area and providing ample space for heat transfer. The design of opposite fluid circulation directions within the two pipes creates a counter-current heat exchange mode. Compared to co-current heat exchange, counter-current heat exchange can maintain a larger temperature gradient along the entire contact length, thereby significantly improving heat transfer efficiency. Attached Figure Description

[0020] To more clearly illustrate the technical solutions in the embodiments of this utility model, the accompanying drawings used in the description of the embodiments of this utility model will be briefly introduced below. Obviously, the drawings described below are merely some exemplary embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on the content of the exemplary embodiments of this utility model and these drawings without any creative effort.

[0021] Figure 1 This is a schematic diagram of the structure of a dual-circulation geothermal energy collection device in one embodiment of the present invention;

[0022] Figure 2 for Figure 1 Top view of the cross section at point AA;

[0023] In the diagram: 1. Heat collection pipe, 2. Heat exchange pipe, 21. Inlet, 22. Outlet, 11. Outer pipe, 12. Inner pipe, 13. Circulation pump, 111. Heat collection zone, 121. Heat dissipation zone, 23. Inlet pipe, 24. Return pipe, 25. First partition plate, 231. Heat exchange zone, 241. Return zone, 242. Liquid passage hole, 14. Second partition plate, 141. Liquid passage chamber. Detailed Implementation

[0024] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the present invention and not intended to limit its scope.

[0025] To keep the drawings concise, each drawing only schematically shows the parts relevant to the disclosure; these do not represent the actual structure of the product. Furthermore, for ease of understanding, in some drawings, only one of components with the same structure or function is schematically shown, or only one is labeled. In this document, "one" not only means "only one," but can also mean "more than one," and "several" includes "two" and "more than two."

[0026] In this document, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to fixed connections, detachable connections, or integral connections; they can refer to mechanical connections or electrical connections; they can refer to direct connections or indirect connections through an intermediate medium; and they can refer to the internal connection between two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.

[0027] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0028] In the description of this embodiment, terms such as "upper," "lower," "left," and "right" are based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of description and simplification of operation, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model.

[0029] Furthermore, in the description of this application, the terms "first," "second," etc., are used only to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0030] like Figures 1-2As shown, this invention illustrates a dual-circulation geothermal energy harvesting device according to one embodiment. Its core components include a heat collection pipe 1 and a heat exchange pipe 2. The heat collection pipe 1 is a closed pipe with a heat exchange medium flowing inside. It is laid in parallel within underground rock strata or soil. The specific laying method can be horizontal layering or vertical drilling, depending on geological conditions. Its function is to absorb underground heat energy through the heat exchange medium. The heat exchange pipe 2 is spatially parallel to the heat collection pipe 1, forming a heat conduction path through physical contact. The heat exchange pipe 2 has an inlet 21 and an outlet 22. The inlet 21 is connected to a surface water source via a water supply pipe, and the outlet 22 is connected to a surface water storage tank via a water supply pipe, forming a surface water circulation loop.

[0031] In terms of fluid circulation design, the flow direction of the heat exchange medium in heat collector pipe 1 is opposite to the flow direction of the water in heat exchange pipe 2. If heat collector pipe 1 is laid vertically downwards, the heat exchange medium in heat collector pipe 1 can flow in from the bottom and out from the top, while the water in heat exchange pipe 2 flows in from the top and out from the bottom, forming a reverse flow. If it is laid horizontally, the heat exchange medium in heat collector pipe 1 flows from left to right, while the water in heat exchange pipe 2 flows from right to left. By installing a circulation drive device (such as a water pump) on the water supply pipeline, the water in heat exchange pipe 2 is ensured to circulate in the set direction, while the heat exchange medium in heat collector pipe 1 circulates by relying on natural temperature difference or the built-in drive device.

[0032] The heat collection pipe 1 and heat exchange pipe 2 are arranged in parallel to form a heat conduction contact, maximizing their contact area and providing ample space for heat transfer. The opposite fluid circulation directions within them create a counter-current heat exchange mode. Compared to co-current heat exchange, counter-current heat exchange maintains a larger temperature gradient along the entire contact length, thus significantly improving heat transfer efficiency. Specifically, at the inlet of heat exchange pipe 2, the low-temperature water comes into contact with the high-temperature heat exchange medium heated underground, rapidly absorbing heat; at the outlet, the heated water comes into contact with the low-temperature heat exchange medium flowing from the surface into the ground, further releasing heat. This achieves full heat exchange, truly extracting heat without extracting water, thus maximizing environmental protection in the use of geothermal energy.

[0033] This structural design effectively solves the problems of unreasonable layout and insufficient heat transfer between the heat collection pipe 1 and heat exchange pipe 2 in existing technologies. By optimizing the fluid flow direction and pipe layout, it enables more efficient transfer of geothermal energy to surface water. After absorbing the heat transferred from the heat collection pipe 1 through the heat exchange pipe 2, the surface water enters the surface water storage tank at a higher temperature, providing a high-quality heat source for subsequent heating, power generation, and other applications, reducing geothermal energy waste and lowering energy utilization costs. Simultaneously, the dual-loop structure operates independently yet interacts with each other. The heat collection pipe 1 focuses on collecting geothermal energy, while the heat exchange pipe 2 focuses on heat output; their collaborative operation enhances the stability and reliability of the entire device.

[0034] like Figures 1-2 As shown, the heat collection pipe 1 and the heat exchange pipe 2 are laid vertically downwards, forming a coaxial nested structure, with the heat collection pipe 1 covering the outside of the heat exchange pipe 2. During construction, a vertical channel is first drilled underground, and the heat exchange pipe 2, consisting of an inlet pipe 23 and a return pipe 24, is placed in the center of the channel. The inlet pipe 23 can be corrugated to increase the heat exchange area and improve the heat exchange efficiency. The inlet pipe 23 covers the outside of the return pipe 24, and a first partition plate 25 is provided at the lower end of the inlet pipe 23. Then, the heat collection pipe 1, consisting of an outer tube body 11 and an inner tube body 12, is nested outside the heat exchange pipe 2. The upper ends of the outer tube body 11 and the inner tube body 12 are connected by connecting fittings, and the lower ends are connected by a circulation pump 13 installed on the inner tube body 12 to form a closed loop. The inner tube body 12 is located inside the heat exchange pipe 2. The circulating pump 13 can be selected from various models such as centrifugal pumps and screw pumps to meet different flow rate and head requirements. The selection of multiple models of circulating pump 13 allows for optimized configuration based on the actual operating needs of the system, improving system efficiency and reliability. A heat collection zone 111 is formed between the outer tube 11 and the inner tube 12, and a heat dissipation zone 121 is formed between the inner tube 12 and the heat exchange pipe 2; a heat exchange zone 231 is formed between the inlet pipe 23 and the return pipe 24, and a return water zone 241 is formed inside the return pipe 24. The upper end of the inlet pipe 23 is the inlet 21, connected to the surface water source's water supply pipeline, and the upper end of the return pipe 24 is the outlet 22, connected to the surface water storage tank's water supply pipeline. Water from the surface water source enters the inlet pipe 23 from the inlet 21 under the action of the water pump, flows downward to the lower end, enters the return pipe 24 through the lower end connecting structure, and flows upward to the outlet 22 in the return water zone 241; the heat exchange medium in the heat collection pipe 1 absorbs geothermal energy in the heat collection zone 111 under the drive of the circulation pump 13, and is pumped into the heat dissipation zone 121 by the circulation pump 13, transferring the heat to the heat exchange pipe 2, and then flows back to the heat collection zone 111 through the upper end connecting point for circulation.

[0035] The vertically coaxially nested structural design creates a ring-shaped heat exchange area between the heat collection pipe 1 and the heat exchange pipe 2 in the vertical direction, increasing the contact area and improving heat transfer efficiency. The layered structure of the heat collection pipe 1 clearly divides the heat collection zone 111 and the heat dissipation zone 121. The heat collection zone 111 directly contacts the underground heat source to absorb heat, while the heat dissipation zone 121 focuses on heat conduction, reducing ineffective heat loss. The nested inlet pipe 23 and return pipe 24 of the heat exchange pipe 2 form a counter-current heat exchange, achieving higher heat transfer efficiency under the same conditions compared to co-current flow, thus increasing the hot water output temperature. The corrugated inlet pipe 23 further increases the heat exchange area, strengthens the heat exchange process, and improves the efficiency of geothermal energy collection. The circulation pump 13 can be installed at the bottom of the well as a submersible pump or above ground, circulating the heat exchange medium within the heat collection pipe 1 through pipe connections. Different installation positions of the circulation pump 13 can be selected for optimized configuration based on actual engineering needs and environmental conditions, improving the system's adaptability and reliability. The first partition plate 25 ensures the fluid independence of the heat collection pipe 1 and the heat exchange pipe 2, preventing mixing and enhancing the stability and safety of the device operation. This overall structural design rationally plans the fluid path and heat transfer path, enabling the geothermal energy collection, transfer, and water heating processes to proceed in an orderly and efficient manner, improving the heat exchange performance and energy utilization efficiency of the entire device.

[0036] like Figures 1-2 As shown, the inlet pipe 23 and return pipe 24 are coaxially arranged. The lower end of the return pipe 24 extends to abut against the first partition plate 25 to ensure a sealing effect between the return pipe 24 and the inlet pipe 23. The inlet pipe 23 can be a tubular heat exchanger, a plate-fin heat exchanger, or a finned heat exchanger, etc., to enhance the heat exchange effect. The lower sidewall of the return pipe 24 has several evenly distributed liquid passage holes 242. When water flows downwards in the inlet pipe 23 to the lower end, it enters the return water zone 241 through these liquid passage holes 242, and then flows upwards to the outlet 22. The size and number of liquid passage holes 242 are designed according to the actual water flow rate and heat exchange requirements to ensure smooth water passage and maintain a suitable water flow velocity.

[0037] The placement of the liquid passage holes 242 optimizes the water circulation path within the heat exchange pipe 2, achieving connectivity between the heat exchange zone 231 and the return water zone 241. The evenly distributed liquid passage holes 242 ensure a more uniform water distribution when entering the return water zone 241, preventing localized water flow obstruction and uneven heat exchange, thus improving the uniformity of the hot water temperature in the return water zone 241. The rationally designed liquid passage holes 242 guarantee water flow rate and velocity, enhancing the heat exchange effect between the water and the pipe wall, further improving the heat exchange performance of the device, resulting in a more stable output hot water temperature. Working synergistically with the counter-current heat exchange structure, it optimizes the overall heat exchange efficiency. Multiple inlet pipe designs 23 can be selected according to different application scenarios and heat exchange requirements, improving the system's flexibility and heat exchange efficiency.

[0038] Based on the structure of the heat collection pipe 1, gravel is uniformly filled inside the heat collection zone 111, with the filling amount reaching a reasonable proportion of the volume of the heat collection zone 111, ensuring that there are appropriate gaps between the gravel to facilitate the flow of the heat exchange medium. During installation, the inner tube 12 and the outer tube 11 are first installed, the heat collection zone 111 is filled with gravel, and then the upper ends of the outer tube 11 and the inner tube 12 are connected and the circulating pump 13 is installed, so that the gravel is in close contact with the underground rock strata and soil, and at the same time, it is in full contact with the heat exchange medium.

[0039] The collector zone 111 is filled with gravel. Utilizing the gravel's large specific surface area and good thermal conductivity, the heat exchange efficiency between the collector zone 111 and the underground rock strata is enhanced, allowing for more effective absorption of geothermal energy and rapid transfer to the heat exchange medium, thus accelerating the heating rate of the heat exchange medium. The gravel also acts as a flow guide for the heat exchange medium, ensuring more uniform flow within the collector zone 111 and preventing insufficient local heat exchange. Combined with the layered structure of the collector pipe 1, this further improves the geothermal energy harvesting efficiency and the overall performance of the device.

[0040] like Figures 1-2 As shown, the base heat exchanger pipeline 1 includes a nested structure of an outer tube 11 and an inner tube 12. A second partition plate 14 is fixedly installed on the inner wall of the bottom of the inner tube 12. The partition plate is parallel to the bottom surface of the inner tube 12 and has a gap between it, forming a liquid passage chamber 141. Several flow channels are opened on the outer peripheral wall of the bottom of the inner tube 12, which is also the outer peripheral wall of the liquid passage chamber 141, so that the liquid passage chamber 141 is connected to the heat collection area 111 between the outer tube 11 and the inner tube 12. The circulating pump 13 is fixed to the second partition plate 14 by bolts or clips. Its inlet end is connected to the liquid passage chamber 141, and its outlet end passes through the second partition plate 14 and extends to the heat dissipation area 121 between the inner tube 12 and the heat exchanger pipeline 2.

[0041] When the device is running, the heat exchange medium in the heat collection zone 111 absorbs heat from the underground rock strata and flows into the liquid-passing chamber 141 through the flow channel. Driven by the circulation pump 13, the heat exchange medium is pumped from the liquid-passing chamber 141 into the heat dissipation zone 121. The heat is transferred to the parallel heat exchange pipeline 2 through the inner tube 12 wall. Then, the heat exchange medium returns to the heat collection zone 111 through the upper end connection between the outer tube 11 and the inner tube 12, forming a closed loop.

[0042] The structural design of the second partition plate 14 and the liquid-passing chamber 141 optimizes the flow path of the heat exchange medium in the heat collection zone 111. The liquid-passing chamber 141 acts as a buffer zone between the heat collection zone 111 and the circulating pump 13, stabilizing the inflow rate of the heat exchange medium and preventing uneven load on the circulating pump 13 due to fluid fluctuations in the heat collection zone 111. The second partition plate 14 provides rigid support for the circulating pump 13, reducing vibration amplitude during pump operation, lowering mechanical losses, and extending service life. The liquid-passing chamber 141 is connected to the heat collection zone 111 through flow channels, ensuring that the heat exchange medium flows evenly into the pump body under the combined action of gravity and the driving force of the circulating pump 13, thus improving the stability of fluid circulation. This structure, in conjunction with the layered heat collection design, makes the geothermal energy harvesting process more efficient and orderly, avoiding the problem of decreased heat exchange efficiency due to unstable fluid flow and ensuring the continuous and stable operation of the dual-circulation system.

[0043] like Figures 1-2 As shown, an insulation layer (not a material limitation, only describing the structural form) is attached to the outer wall of the return water pipe 24 of the heat exchange pipeline 2. This insulation layer continuously covers the return water pipe 24 along its axial direction, and a sealed structure is used at the connection between the return water pipe 24 and components such as the second partition plate 14 and the inner pipe body 12 to prevent heat loss from the connection gaps. The return water area 241 inside the return water pipe 24 is adjacent to the heat dissipation area 121. The heat from the heat dissipation area 121 is transferred to the wall of the return water pipe 24 through the inner pipe body 12, heating the water flow in the return water area 241.

[0044] The insulation structure of the return water pipe 24 works in conjunction with the heat dissipation zone 121 for heat conduction: the insulation layer reduces heat loss during the upward flow of hot water in the return water zone 241, allowing the hot water heated by the heat dissipation zone 121 to be transported to the ground surface at a higher temperature, forming a complete heat utilization chain of "collection-transfer-insulation" with the circulation path of the heat exchange medium in the heat collection pipe 1. The combination of the two ensures the effective transfer of geothermal energy to the water body, and reduces energy loss during the transmission process through the insulation design, thereby improving the overall energy efficiency of the entire device.

[0045] like Figures 1-2 As shown, the inlet pipe 23 consists of multiple segmented pipe bodies, each with a flange at both ends. The flanges of adjacent pipe segments are connected by bolts and gaskets to form a sealed piping system. The flange connection facilitates the installation and disassembly of the inlet pipe 23 while ensuring the piping's tightness. The segmented splicing structure of the inlet pipe 23 can adapt to different installation environments and construction requirements, improving the system's scalability and maintainability.

[0046] The segmented, modular inlet pipe structure facilitates transportation and installation, and can adapt to underground environments at varying depths. Flange connections ensure the pipeline's airtightness, preventing water leakage and improving system reliability and stability. This structural design effectively isolates groundwater, preventing direct contact between groundwater and the heat exchange medium, achieving the environmentally friendly goal of heat extraction without water extraction, and minimizing the impact on groundwater resources.

[0047] like Figures 1-2 As shown, in the dual-circulation geothermal energy collection device, the outer tube 11, inner tube 12, inlet pipe 23, and return pipe 24 are all coaxially arranged. The outer tube 11 is the outermost structure of the heat collection pipeline 1, and its central axis coincides with the central axis of the inner tube 12. The inner tube 12 is located inside the outer tube 11, forming a heat collection zone 111 between them. The inlet pipe 23 is located inside the inner tube 12, and its central axis coincides with the central axis of the inner tube 12. The return pipe 24 is located inside the inlet pipe 23, and its central axis also coincides with the central axis of the inner tube 12.

[0048] This coaxial structure achieves precise installation through a positioning device, ensuring uniform spacing between each layer of pipes. In heat exchange pipe 1, the heat exchange medium flows in the heat collection zone 111 between the inner tube 12 and the outer tube 11; in heat exchange pipe 2, cold water flows from top to bottom through the annular space between the inlet pipe 23 and the return pipe 24, absorbs heat, and then returns to the ground from bottom to top through the return pipe 24. The pipes are connected by a sealed system to form a complete circulation system, ensuring stable fluid flow within their respective circulation paths.

[0049] The coaxial arrangement of the outer tube 11, inner tube 12, inlet pipe 23, and return pipe 24 makes the entire device more compact and rational in structure, reducing the floor space and installation space requirements. This arrangement ensures that the heat collection zone 111 and the heat exchange zone 231 form a uniform annular space, ensuring that heat can be evenly transferred in the radial direction, avoiding local overheating or undercooling, and improving heat exchange efficiency.

[0050] The coaxial structure simplifies pipe connections and fluid flow paths, reducing system resistance and energy consumption. Simultaneously, the uniform spacing between pipes facilitates the installation of insulation materials and maintenance. In practical applications, this structural design can adapt to drilling operations under different geological conditions, improving the adaptability and reliability of the device and providing strong support for the efficient extraction of geothermal energy. Through a closed circulation system and sealed structure, the device effectively isolates groundwater, preventing pollution of groundwater resources and achieving a green and environmentally friendly method of geothermal energy utilization.

[0051] It should be noted that the above embodiments are only used to illustrate the technical solution of this utility model and are not intended to limit it. Although this utility model has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solution of this utility model without departing from the spirit and scope of the technical solution of this utility model, and all such modifications or substitutions should be covered within the scope of the claims of this utility model.

Claims

1. A dual-circulation geothermal energy harvesting device, characterized in that, include: The heat collection pipeline (1) is a closed pipeline with a heat exchange medium flowing inside. The heat collection pipeline (1) is laid in underground rock strata or soil for collecting underground heat energy. The heat exchange pipeline (2) is arranged in parallel with the heat collection pipeline (1) and forms a heat conduction contact. The heat exchange pipeline (2) has an inlet (21) connected to the surface water source through a water supply pipeline and an outlet (22) connected to the surface water storage tank through a water supply pipeline. The circulation direction of the fluid in the heat collection pipe (1) is opposite to that in the heat exchange pipe (2).

2. The dual-circulation geothermal energy harvesting device according to claim 1, characterized in that, The heat collection pipe (1) and the heat exchange pipe (2) are laid in a vertically downward direction. The heat collection pipe (1) and the heat exchange pipe (2) are nested together. The heat collection pipe (1) is wrapped around the outside of the heat exchange pipe (2).

3. The dual-circulation geothermal energy harvesting device according to claim 2, characterized in that, The heat collection pipeline (1) includes an outer tube (11) and an inner tube (12) located inside the outer tube (11). The upper end of the outer tube (11) is connected to the upper end of the inner tube (12), and the lower end of the outer tube (11) and the inner tube (12) are connected through a circulation pump (13) installed on the inner tube (12) to form a closed loop. The heat collection pipeline (1) is located inside the inner tube (12). A heat collection area (111) is formed between the outer tube (11) and the inner tube (12), and a heat dissipation area (121) is formed between the inner tube (12) and the heat exchange pipeline (2).

4. The dual-circulation geothermal energy harvesting device according to claim 3, characterized in that, The heat exchange pipeline (2) includes an inlet pipe (23) and a return pipe (24) located inside the inlet pipe (23). The inlet pipe (23) is wrapped around the outside of the return pipe (24). The lower end of the inlet pipe (23) is provided with a first partition plate (25) to seal the heat collection pipeline (1) and the heat exchange pipeline (2). The lower ends of the inlet pipe (23) and the return pipe (24) are connected. A heat exchange zone (231) is formed between the inlet pipe (23) and the return pipe (24). A return water zone (241) is formed inside the return pipe (24). The upper end of the inlet pipe (23) forms the inlet (21), and the upper end of the return pipe (24) forms the outlet (22).

5. A dual-circulation geothermal energy harvesting device according to claim 4, characterized in that, The lower end of the return water pipe (24) extends to abut against the first partition plate (25) and has a plurality of liquid passage holes (242) on its side wall. The liquid passage holes (242) are used to connect the heat exchange zone (231) and the return water zone (241).

6. The dual-circulation geothermal energy harvesting device according to claim 3, characterized in that, The heat collection zone (111) is filled with gravel, which is used to enhance the heat exchange efficiency between the heat collection zone (111) and the underground rock strata.

7. A dual-circulation geothermal energy harvesting device according to claim 4, characterized in that, The inner wall of the inner tube (12) is provided with a second partition plate (14), and the circulation pump (13) is installed on the second partition plate (14). A liquid passage cavity (141) is formed between the second partition plate (14) and the bottom surface of the inner tube (12). The liquid passage cavity (141) is connected to the heat collection area (111). The circulation pump (13) is used to pump the heat exchange medium in the liquid passage cavity (141) into the heat dissipation area (121).

8. A dual-circulation geothermal energy harvesting device according to claim 4, characterized in that, The wall of the return water pipe (24) is made of heat-insulating material to reduce the heat loss of the hot water in the return water pipe (24).

9. A dual-circulation geothermal energy harvesting device according to claim 4, characterized in that, The water inlet pipe (23) is a segmented splicing type, and the connection of the water inlet pipe (23) is through flange.

10. A dual-circulation geothermal energy harvesting device according to claim 7, characterized in that, The outer tube (11), the inner tube (12), the inlet pipe (23), and the return pipe (24) are all coaxially arranged.

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